珠一凹陷古近系复杂断裂区成像技术研究与应用

Research and Application of Imaging Technology in Complex Fault Area of Paleogene in Zhuyi Sag

南海北部珠江口盆地珠一凹陷古近系复杂断裂区域是油气运聚和成藏的有利区带,勘探潜力巨大。但古近系地层埋深大,横向速度变化快,存在地震成像不清的问题,且复杂断裂区地震波反射路径复杂,成像更加困难,严重制约了该区油气勘探进程。通过采用高精度宽频处理技术,提升地震中低频段信号的反射质量;然后引入地质约束速度建模,采用基于稳定低频信号模型的高精度速度反演,改善叠前深度偏移成像效果,提升了古近系复杂断裂区成像质量。

The complex fault area of Paleogene in Zhuyi Sag,the Pearl River River Mouth Basin,northern South China Sea,is a favorable zone for oil and gas migration and accumulation,with great exploration potential.Howev⁃er,the Paleogene strata have a large burial depth,rapid lateral velocity changes,and there is a problem of un⁃clear seismic imaging.In addition,the seismic wave reflection path in complex fault areas is complex,making im⁃aging more difficult,which seriously restricts the oil and gas exploration process in this area.Firstly,high-preci⁃sion broadband processing technology is used to improve the reflection quality of low-frequency signal in earth⁃quakes;Then,geological constrained velocity modeling is introduced,and high-precision velocity inversion based on stable low-frequency signal model is used to improve the imaging effect of pre-stack depth migration and enhance the imaging quality of complex fault areas in the Paleogene.